Energy transfer in linear chain manganese salts: Emission spectra of CsMnBr3, RbMnBr3 and CsMnI3 crystals doped with Er3+

The luminescence spectra of CsMnBr3, RbMnBr3 and CsMnI3 crystals doped with Er3+ have been investigated in the 10–300 K temperature range. These linear chain manganese salts behave as “pseudo” one-dimensional antiferromagnets. The temperature dependence of luminescence from the doped materials indicates a rapid thermally activated transfer of excitation energy from the Mn2+ ions of the bulk crystal to the Er3+ impurity centers. Analysis of the data suggests that energy migration occurs by two distinct processes with activation barriers of: 200 and 500 cm−1 for CsMnBr3, 180 and 500 cm−1 for RbMnBr3 and 300 and 650 cm−1 for CsMnI3. The behavior of CsMnxCd1-xBr3 crystals containing Er3+ clearly indicates that the process with the higher activation barrier corresponds to two- or three-dimensional exciton migration.